The orthodontic forces applied to the dentition and the resistance the periodontics offers to these forces control the resulting tooth movement. The rationale of this research is to provide the orthodontist with the clinical instrumentation with which to measure the forces and couples produced by the appliances in the oral cavity. With these instruments, the relation between the applied force system and the resulting clinical tooth movement can be defined without the simplifying assumptions inherent in laboratory studies. Irrespective of the technique practiced, such instruments provide individual orthodontist with the ability to define treatment protocols and reactivation regimens, to fabricate specialized appliances for individual treatment, to introduce new products to their practice with greater confidence in their use, and to conduct studies which will add to the common knowledge base. An appliance system designed on a "force driven" concept is to be constructed. This appliance system, by utilizing these newly developed instruments, allows accurate control and variation of the boundary conditions at each attachment hence providing improved biomechanical control of tooth movement.